


Agape

by dearcecil



Category: Sherlock (TV)
Genre: Alternate Universe - Gender Changes, F/F, F/M, M/M, Rule 63, Threesome - F/M/M
Language: English
Status: Completed
Published: 2011-11-23
Updated: 2011-11-23
Packaged: 2017-10-26 11:11:25
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 7,783
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/282368
Author URL: https://archiveofourown.org/users/dearcecil/pseuds/dearcecil
Summary: <blockquote class="userstuff">
              <p>One day, Joan Watson trips and falls through a door that lands her in 221B. Except this 221B does not house the eccentric, madwoman Sherlock Holmes and her esteemed associate, Dr. Watson. No, this one has a very male Sherlock Holmes and Dr. Watson.</p>
<p>Joan and John fall for each other, and Sherlock, as usual, finds himself happily in the middle of things.</p>
            </blockquote>





	Agape

**Author's Note:**

> [the prompt](http://sherlockbbc-fic.livejournal.com/12826.html?thread=68089114)
> 
> was on page 31 of part 21 of the sherlock kink meme

Joan stares up to the shelf at the top of the closet, furrowing her brow. "Sherlock," she calls, turning around, "what did you want me to do here?"

"Box on top shelf," Sherlock calls back from the kitchen. "Need it!"

"Well, then grab it yourself," Joan says, planting her hands on her hips. She's not going to mention that she can't reach the top shelf, but Sherlock already knows that anyway; Joan can practically see her smirking.

"Preoccupied; I expect you don't want me to burn down the flat," Sherlock replies. "There's a step stool somewhere around the flat, Joan, just pick it up and you'll be—oh, no, hm, that's interesting. Very interesting, indeed..." Sherlock's voice trails off, and Joan hears hissing from the kitchen that she's come to associate with certain acids. She huffs a sigh, lamenting the fact that she identifies acids with any sounds at all.

"Don't melt through the counters! Mrs. Hudson will have our heads for it!" Sherlock gives a distracted mumble in response and nothing more, and really, Joan just needs to stretch up and reach the top shelf _now_ , so she can go to the kitchen and deal with this and not have Sherlock whine her ear off for not getting the damn box. She steps into the closet and stretches up onto the tips of her toes, grasping for the shelf and not bothering to hold the door open. Her fingertips scrape the edge of the shelf, she pulls herself up, and—

The closet door slams shut as a gust of wind trails through the flat, and she just barely hears Sherlock wonder aloud, "Why the hell are the windows all open?" as if she hadn't opened them fifteen minutes prior. The closet light flickers. Joan slides the box an inch, grunts, and turns to open the closet door. The first thing she notices is that the windows are all closed. The second thing she notices is that the flat reeks inexplicably of male deodorant.

The third thing she notices is the man staring at her and, God, is that _her gun_ in his hand? Bloody hell. She wonders where Sherlock is; if anyone's laid their hands upon her, Joan refuses to be held responsible for her actions against them.

"Who are you?" the man asks steadily.

"I could ask you the same thing," she counters. Her hands feel far too empty without her Browning, and the ease with which he's holding _her gun_ grates against her like sandpaper.

"No, you really couldn't," the man says, "considering this is _my_ flat, and you've just stumbled out _my_ closet."

As if someone holding _her gun_ wasn't enough, he had to be insane. Lovely. "I think you'll find this is my flat, actually. My name's on the lease, right with my flatmate's. Binding legal contracts are difficult to contradict, gun or no." He raises an eyebrow, and she raises one right back. His hands are so steady that she might approve, were he not holding her at gunpoint with _her own damn gun_. "Now who the hell are you?"

"John Watson," he says cautiously. "Who the hell are you?"

Joan furrows her brow. It must be a coincidence, or some sort of ploy. "Joan Watson."

John narrows his eyes at her, looking just as confused, but he doesn't let up with _her bloody gun_ , and she respects him a bit for that, although a real gentleman would give her a chance to take back _her fucking gun_ and maybe break a bone or two. Or six. Or just whatever number feels right, she isn't picky. "Prove it."

"Excuse me?"

"Prove your identity."

Joan doesn't roll her eyes, but she's sure her desire to is clear in her tone. "Yes, of course, I carry about proof of identity whenever I traipse about the flat. Let me just get that out, then."

"Oh, _this_ is interesting," a man's voice says from behind her, and Joan doesn't turn around, because there's (probably) only one gun in the room. Still, it bothers her that she didn't notice his entrance, and being trapped in her own hallway by two strange men, one holding _her goddamn bloody gun_ , positively rankles. "John, why are you holding your sister at gunpoint? I'm supposed to be the terrible host, not you."

John furrows his brow, and Joan does the same. "She's not my sister, Sherlock." Joan's eyebrows fly up at the man's name, but John keeps talking. "I've no idea who she is. She introduced herself as _Joan_ Watson, but obviously that's not right; it's just a lazy revision of my own name."

Joan scoffs. "No, that's what your name is of mine."

"Oh," the man calling himself Sherlock whispers behind her, and for a moment she feels electrified because that is the exact tone Sherlock uses when she's discovered something exciting. " _Oh_ ," he says again. He claps his hands. "Oh, this is fantastic, this is—" He grabs her by the shoulders and whirls her around, and she grabs him by the neck and goes to knee him in the groin, and he presses down _just so_ on her shoulder like he knows her scar is there (but how could he?), and oh, God, that really burns, and her grip on his neck slackens and he wipes her hand off like it's nothing and looks at her.

His eyes are just like Sherlock's. Joan's hands fall to her sides uselessly, because there is no one, _no one_ , with eyes like that. She has never met anyone other than Sherlock with eyes like that. She can feel him picking her apart as his eyes dart side to side, and he stares at her, and it's just like when she first met Sherlock. It's exactly like that. She feels more than hears her own breath hitch.

"Sherlock, what the hell is going on?" John asks. He's still got the gun on her. Of course he does, Joan thinks hysterically; it's exactly what she would do, if this happened to her and Sherlock, and... that is what's happening, isn't it? This is happening to her and to Sherlock, but to them as men, and that doesn't even begin to make any sense; maybe Sherlock's experiment went horribly awry and this is a hallucination caused by the fumes, maybe she's been drugged, maybe she dropped the box on her head and she's unconscious and this is some terrible dream—

Sherlock backs away, looking immensely pleased. He grabs Joan's hand and smiles. "Hello, Joan." He glances at John, still holding Joan's hand. "I have no idea. Isn't it wonderful?" John looks him in the eye, and Sherlock shakes his head, and Joan is completely thrown by this because she can read their expressions perfectly, because they look just like her own and her Sherlock's. Wait, _her_ Sherlock's? She doesn't need to mentally separate them, because there is no way this man is the male version of Sherlock, and yet—

And yet his dark purple shirt is the same. His hair, his eyes, his facial structure, his long fingers and his pale skin. The way he holds himself, the way he looks and speaks and thinks louder than anyone else in the room. And the way John relaxes reluctantly, his body settling down in precisely the way her own would; the way he keeps his gun in his hand, because it has to be _his_ gun, doesn't it? Because she's not in _her_ flat at all, is she?

Sherlock looks between Joan and John, and his manic grin cements it. "Tea, then?"

* * *

John, despite his confusion and caution, moves steady sureness, clearly comfortable in a kitchen littered with half-finished experiments and fingers on the counter, a kitchen that Joan knows like the back of her hand, yet doesn't know at all. Watching him, it all seems so obvious, but it can't be. It shouldn't be. But his striped jumper is identical to the one in her closet, and his hair, and his height, and... He stretches up a bit to get mugs, and his left arm is hampered by what the voice in the back of her head says is a bullet wound acquired in Afghanistan, a wound that's left a nasty scar that still aches and makes stretching harder than it has a right to be and that's left him with nerve damage he doesn't like to discuss.

John looks at her, and she feels her knees go weak, because those eyes are _hers_ , that guarded expression is _hers_. "Dash of milk," she answers before he can ask. "One sugar."

John does the same for his own tea. The third mug gets two sugars, and Joan knows it is for Sherlock, and Joan knows he'll only drink a third of it to appease John and then leave the rest to get cold until John pours it down the sink right before bed. She clutches her own cup of tea like it's the only rock in a roiling sea, and hell, what an awful rock to choose; it's just as likely to get swept away as she is, and then all of her tea will be full of seawater, won't it? Joan drowns hysterical laughter in her cup.

John puts his cup to his lips, and Sherlock, who has been looming in loud silence for the past few minutes, finally bursts. "How did you get here?" he demands.

"Closet," Joan says. "Door shut, opened it, walked out here instead of my own flat." She sips at her tea, her perfectly made, familiar tea, and something in her threatens to crumble, so she reinforces it with steel and sits up straighter than before. "If Sherlock hadn't made me try to get that box—"

"There's another me?" Sherlock asks happily.

"What box?" John asks, much less happy.

"Box on the top shelf. She needed it." Joan drains her cup, and sets it on the table next to something that looks like a human eye in a bowl. She looks at Sherlock, and frowns. "I wouldn't call her another you. It's more like you're another her, really."

"Wonderful," Sherlock says.

"A box like this?" John asks, holding up a cardboard box; she hears clinking, and presumes it's full of glass. Probably chemistry equipment. She notices John finished his tea almost immediately after she did.

"I don't know. I never managed to get it down," she admits. "The wind blew the door shut before I could grab it. Sherlock left all of the windows open in the flat."

"I closed the windows because it was getting drafty," John says. He looks her in the eye, and Joan can pinpoint the moment he has the revelation she had, because his shoulders relax and tense again just as hers did, his dark eyes pierce into her own, his brows draw together for just a moment before his expression falls. She knows he's hit the same odd acceptance she has. She just knows. "So... Joan."

"John." She nods to him.

"...right." He nods back.

Sherlock is looking between them like he's discovered the mother lode. "Tell me more about your version of me."

* * *

"...and so I shot him," Joan says, "because otherwise that idiot would have taken the pill and killed herself, and I wasn't about to look for another flatmate."

John smiles, nodding in commiseration. "He did the same thing, of course. Sherlock's always trying to prove he's cleverer than everybody else."

Joan rolls her eyes, taking a sip from her third cup of tea. "You're telling me. Always getting into fights without me, refusing to open the door when she breaks into another bloody flat—"

"Yes, and then getting so touchy when I'm bothered by that—"

"I don't like the turn this conversation has taken," Sherlock says, looking between them like he's discovered a bomb. John and Joan ignore him with the same turn of their shoulders, and lean in closer to talk about Sherlock's annoying habits that apparently transcend space, time, and gender. "We should get you back."

"Feel free to figure it out, then," Joan says.

"It'll be a lovely mystery for you," John says. "Does your Sherlock do the thing with the nicotine patches?"

"If I hear the words 'it's a such-and-such-number patch problem' again, I will flay myself. It's like she _wants_ to die, it's infuriating."

Sherlock leaves the kitchen to investigate the closet while John hums in agreement.

* * *

John looks at Joan, really _looks_ at her, while she speaks. They both finished their tea long ago, the cups now soaking in the sink beside beakers and flasks, but they're still chatting in the kitchen like a couple of old hens. It isn't something he's really used to, but it feels natural, with Joan. He supposes it makes sense; they obviously have a lot of common ground, being alternate versions of each other and all. Still, for all their similarities, he's noticed some differences.

The clearest is, of course, that she is a woman. She's wearing a sweater covered in Scotties that John remembers seeing when he bought his black cat sweater. It fits her perfectly, hints at the curves of her body, and his eyebrows draw together because in a way it's... sort of his body. But it's not. It's his female self's body. And his female self is not him, she's just a lot like him, having generally led the same life, but not.

He's only distracted because it's strange to see his female counterpart, nothing more.

Right.

"I'm sorry, what?" John asks, realizing he's missed the past few sentences. Joan is silent, looking at him like she can read his mind, resting her chin on one hand.

"It is a bit odd, isn't it? Don't worry, I've been distracted by pretty much the same thing." Joan's wry smile is achingly familiar. "Never thought I'd see myself with stubble."

"Never thought I'd see myself with shoulder length hair." John smiles back. "It's a lot to take in."

They smile at each other like that for a few moments, taking in details that are at once old and new, and with anyone else John is sure he would feel quite awkward. The speculation comes to a halt when Sherlock returns, looking annoyed and excited simultaneously, holding his cell phone. "Lestrade has a case." He looks at John, then Joan, and frowns. "You're a doctor," Sherlock says to Joan.

"Yes."

"You go on cases with your Sherlock." Joan nods, and Sherlock nods back. "All right, you can come. Take John's other coat." He leaves the room, texting Lestrade, and John shares a half-pleased, half-exasperated grimace with Joan that is well-practiced on either end.

* * *

Sherlock gazes out the window of the cab as John and Joan chat quietly, probably talking about themselves some more. One of John's thighs is pressed against Sherlock's, and the other is pressed against Joan's. He wonders if John has acknowledged his latent attraction to her yet, and if he has, whether or not he's twisted himself up over it.

John lets out the same little laugh he uses when Sherlock does something he considers endearing, and Sherlock restrains a smirk. He's noticed it and denied it, then. Typical John.

He doesn't judge John for his attraction, not at all. Perhaps it's narcissistic in a way, but Sherlock considers that unimportant; John should appreciate himself more anyway. Besides, Joan is just John's type (blonde, short, laughs at his jokes), but with the very welcome twist of not being completely dull. Sherlock finds her physically attractive in many of the ways he finds John attractive, although her hair is longer, her chest is rather more developed, and her jaw is softer. They have the same nose, the same eyes, the same tan and tired look, but it's all wrapped up in something hard yet feminine, and it is pleasant.

Were he to meet his female counterpart, Sherlock thinks he might have a similar reaction, although it is equally likely that they would despise each other; guessing at the outcome is useless, as he lacks data, so he dashes his theories away and focuses on how both John and Joan flirt with their hands, and their shoulders, and their laughs. Joan rests her hand on her thigh, the side of it just barely touching John's leg, and Sherlock estimates that one or both of them will have a sexual identity crisis within the next eight hours, or fewer if he solves this case quickly, which he will. He's already halfway to the conclusion as it is.

Joan brushes her hair behind her ear, and John's hands fall down to his thighs, one brushing against Joan's hand while the other presses against Sherlock's leg. Of course, Sherlock thinks; John is most likely trying to reassure himself of his attraction to Sherlock, and using it to explain his feelings. Sherlock drops his hand down to cover John's, swipes his thumb over John's knuckles, and watches Joan's eyebrows twitch upward in the reflection on the window. She shrugs, leans over to tell John some kind of joke, and they laugh together again.

Sherlock wonders if his female counterpart is in a relationship with Joan. It seems probable; almost everything else has been mirrored thus far, and she is evidently comfortable with their handholding. Then the cab stops, and he pushes all of those thoughts away as he opens the door, because now he's on the case.

* * *

As she barrels through the narrow alley, dodging garbage bins and splashing through puddles, Joan wishes she had her gun. She would feel a damn sight better if she had the weight of it in her hand as she chases after Sherlock, who is chasing after an apparent killer, who is chasing after some faint glimmer of hope that he'll evade capture, and who has left behind a very jarring trail of dead women. At that thought, part of her reconsiders the gun; she's not sure whether she'd like to shoot him or to bash his teeth in like he'd done to four of his victims.

The alleyway is constricting with the four of them packed into it, but it hardly matters. Sherlock is gaining on the man, and Joan doesn't have to glance at John, barely has to spare him a thought, before they're both speeding up in tandem. Sherlock is brilliant, and they both know by now that he can care for himself, know how strong he is, and yet there is a _jolt_ in the pit of Joan's stomach, something that tugs sharply at her insides and propels her forward, and with John beside her it's almost like she's faster, like she's competing with him, competing with herself—

She and John overcome Sherlock, then slam into the suspect simultaneously, driving him mercilessly into the cold asphalt. Joan digs her knee savagely into his back, and when she looks up, John's face is carved from steel, and she thinks, "oh." He meets her eyes, and gasps shortly before they both come back to themselves, flipping the man over. It doesn't take a medical expert to see he's twisted his ankle, and Joan decides to worry about the nasty thrill of pleasure that gives her later, when she's feeling less like she's been electrified.

Sherlock strides up, oozing pleasure and smugness and excitement, and Joan stands, shoving her hands into the pockets of the brown coat she borrowed from John, focusing on the bits of lint between her fingers as she watches Sherlock grill the man on the ground. He can't be more than twenty, and he's curling up around his wound, groaning and sobbing like the world is going to end just because he's sprained his ankle.

"Are you all right?" John asks, walking around to meet her.

Joan looks at him evenly. "I'm fine." She wonders if her pupils are as blown as his are.

Probably.

He lets out a shuddering breath, and her lips twitch, and they turn away from the man on the ground because it would be awfully inappropriate to giggle in his face, wouldn't it? Their shoulders brush together, and she thinks, "what the hell?"

* * *

Sherlock smiles down at Lawrence Berkins, despite his being a man who deserves no smiles at all, because he can tell the exact moment when Joan leans over to kiss John without having to look. Joan sighs, and John's breath hitches in his throat; he makes an eager little noise, and from the rustling of his coat Sherlock is fairly sure he's reaching up to touch Joan's hair, although it is also possible he is touching her neck. John enjoys touching people's necks.

Berkins whimpers up at him pathetically.

"Be quiet," Sherlock snaps. He stands, rests one foot directly on Berkins' sprained ankle, then pulls out his phone to text Lestrade—but first, he turns, and snaps a photo of Joan and John kissing. The sound of the shutter pulls them back to Earth, and they both look at him sheepishly, John opening his mouth to stammer out some unnecessary apology. "Six hours and twenty-seven minutes!"

John halts around a half-formed word, frowns, then tries again. "What?"

"Six hours and twenty-seven minutes since we left the cab, which makes it six hours and thirty-three minutes since I predicted this would happen, and seven hours and twelve minutes since I deduced you were attracted to one another." He snaps a photo of Berkins and sends it to Lestrade, along with their location and a reminder of Sherlock's greatness.

"You're not upset?" John asks. Joan's expression matches his, a charming mixture of perplexity, guilt, concern, and what Sherlock can identify as attraction only because John has been generous enough to teach Sherlock what that looks like when it's directed at him. He straightens up, grinding his foot downward enough that Berkins won't be getting up to hobble away anytime soon, and arches a brow.

"Should I be?" He looks between them. "If she was just any woman, I would be very annoyed, yes, but she _is_ sleeping with me in an alternate universe, so I really can't hold a grudge."

Joan's face goes red, and when John glances at her, he goes red as well. Sherlock's lips twitch, nearly becoming a smile, because that is another thing he has gotten correct while working with insufficient data, and really, he is _so_ good at this. He pats both of them on the shoulder, then strides through the alley to the street. "Lestrade will be here soon; I'd rather not get questioned, although if you're both interested in catching flies with your mouths, I will do my best to be sensitive regarding Watson traditions." After a pause, they fall into step behind him, their footfalls synchronized, and Sherlock smirks. Yes, he is _very_ good at this.

"Taxi!"

* * *

Joan holds in her question even though she feels like she's about to burst at the seams, frowning as one side of her presses against John and the other presses against the door.

"Just ask," Sherlock finally says, and he has the same smug turn to his lips that Joan has seen countless times, but on a slightly different face.

"How'd you know?" she asks. "How could you possibly know that we're involved? She isn't even here."

"Me," Sherlock responds cryptically.

"What?" Joan and John ask at the same time, and they spare a moment to smile at each other before she presses Sherlock again. "What do you mean?"

"When you first arrived, you didn't believe John was the male version of you, quite sensibly of course. Who would ever believe such a ridiculous claim, especially when held at gunpoint? Not you, never; you're too practical and too stubborn to accept a story like that. It was only when I entered—or, rather, when you saw my face—that you started to believe it might be true. You immediately trusted me more than you trusted John.

"Once I realized you weren't his sister, I paid more attention, and of course you betrayed your matching shoulder wound when you moved. There are myriad similarities that I doubt I need to explain anymore, you both have noticed them yourselves, but they were important. When you looked into my eyes, you stopped trying to attack either of us, and soon became acquiescent. Because you, a female alternate of John, existed, I concluded that the female alternate of me must also exist.

"I guessed your likeness to John extended to my counterpart and myself as well, and consequently, to our relationship; John and I are intimately involved, so either you and the female Sherlock were as well, or you were getting there. I admit I was unsure until I noticed the way you looked at my mouth in the kitchen, then later in the cab. It was all quite obvious, really." He smirked. "As for your and John's mutual attraction, well, even a rock could have perceived what the glances between you two meant."

Joan and John stare at him, open-mouthed, and the cabbie furrows his brow at them in the rearview mirror. "That was astounding," Joan says. "But—"

"But?"

"But that makes absolutely no sense," John says, picking up Joan's line, "because parallel universes and parallel... personas... don't make any sense. At all. Why would you believe she's from an alternate universe? Why would you think anything you've just explained? Just... what?"

Sherlock looks at them both with that condescending sort of pity he musters up whenever he believes people are being particularly stupid. "Of course I believe in multiple universes, John, it's simple quantum mechanics."

John shakes his head, and Joan pinches the bridge of her nose. "Of course. Right. And you're not upset about..." She waves her hand vaguely between herself and John. "You know, this?"

The cab stops in front of 221B. "Certainly not," Sherlock says, opening the door. "I would never deny you the pleasure of masturbation."

John practically throws the money at the cabbie, who looks pleased to have them out of his cab and ready to scrub them from his memory, and Joan turns over Sherlock's words in her head. She supposes it is a kind of masturbation, in a very roundabout way. "Huh."

Before John can hurry out of the cab, Joan grabs his wrist, and he turns. They hesitate a moment before pressing their lips together again. "Well... they do say regular masturbation builds up one's resistance to infection," she mumbles into his mouth, and he barely manages to pull her out onto the sidewalk before they both dissolve into giggles for the second time in an hour.

* * *

John thinks, as he walks up the stairs laughing over awful masturbation jokes, that this is terribly inappropriate. He doesn't care, not even when he and Joan reach the doorway and Sherlock looks at them, his gaze keen, dissecting. There's a warmth curling in the pit of his stomach that he knows well, and suddenly it's the easiest thing to lean over and kiss Joan. She tastes like tea and mint and something dark and heady that John almost doesn't notice, because it's almost exactly the taste of his own mouth, which is both alarming and comforting.

Sherlock crosses the room silently, but his scrutiny is like a weight, pressing down on the both of them. It's not unpleasant, though; instead it galvanizes John, and seems to do the same to Joan, if the probing of her tongue is any indication. He rests his hand on the side of her neck, and she runs a hand through his hair, and he explores her mouth. John moans in consideration when he finds that Joan even has the same chips and grooves in her teeth that he has, that he has grown incredibly familiar with after decades of running his teeth over them and biting his cheeks and glancing at his x-rays in the dentist's office.

He pulls her in close, their hips pressed together, and intends to see what else is similar until Sherlock hums. Joan and John pull away, and John notes her lips, swollen and red and glistening in the dim light of the flat. "Yes?" he asks.

Sherlock stares at them the way he sometimes stares at clues during his cases, like if he watches them long enough, or looks hard enough, he can unravel all the secrets of the universe. He's set this look upon John before, but it still sends tingles through his spine, and Joan presses more tightly against him. Sherlock's smile unfurls like a scroll. "Perhaps this would be better suited for the bedroom."

Joan grins. "John's, then," she says, patting his side as though he needs to be identified. "Your room is probably as much of a mess as my Sherlock's. The only thing more shocking than feeling three hands when you're expecting two, is feeling three hands and realizing one's ice cold and cut off at the wrist."

Sherlock's laugh is deep and rich and dusky, and John wonders if he should be worried when his lust coils more tightly despite the matching memory of cold, dead fingers bright in his mind. Instead, he chooses to focus on making it up the stairs.

* * *

John's room is just like Joan's, except for two things: It smells like men's deodorant, and the closet and the hamper are full of men's clothing. Otherwise, it's so similar that she's very nearly floored by the sense of _home_ it brings, so she distracts herself from it by guiding John to his bed. She presses him into it, and he falls onto his back, knees bent and feet firmly planted on the floor. Joan leans down to kiss him again, marvels at how much she knows him without knowing him at all; his sensitive spots might as well be flagged, and hers as well, she thinks, because no one has ever found that spot behind her ear so quickly, not even Sherlock.

At that thought, she turns to look at him, tucking her hair behind her ear. His gaze pierces her more thoroughly than even the bullet that ripped through her shoulder, and she shudders, feeling naked despite her layers. Sherlock, her Sherlock, has impaled her like this before, has left her raw like this before, and it sets fires in her head and her heart and her hips all at once. John takes advantage of the moment, reversing their positions, kneeling between her legs and pushing her sweater up to pour kisses onto her stomach.

He swipes his tongue across her hip, just above her jeans, then kisses back up until his lips are on the middle of her chest. She tugs her shirt and her sweater over her head, dropping them onto the floor without a care, and they push and pull each other until they're fully on the bed and Joan can drop her head onto a pillow. Sherlock looms in the doorway, evidently content to stand and watch, and Joan gulps.

John's teeth scrape over her shoulder, and she digs her nails into his back. When he looks up, she catches his eye, and it's as though something clicks. She's never seen herself wearing the expression that they both don now; everything that's happened thus far has been new, sensational, causing an odd tune to trill and tumble in her chest, and as she sits up to let John deftly unhook her bra, it's like a harmony is being added.

Joan knows her body, and she's unbothered when John tosses her bra in the direction of her sweat; unashamed when not just one, but two gazes rake down her chest. Joan hooks her fingers under John's sweater and tugs off his clothes, exposing his back and chest and stomach and shoulders and arms, throwing them carelessly to join the pile of her clothing.

His body is broad and hard and angled in ways that hers is not, has hair in patches where she has only skin, but his scars are hers, his birthmarks are hers. They lean toward one another, foreheads touching, and she looks at him, and he looks at her, and Joan is never going to be the same, not now that she's seen this. Seen herself (but not herself) laid bare and raw in ways that are terrifying and that resonate in her bones, in ways that make her feel old as dirt and new as every speck of energy crackling between them.

Something, somewhere deep inside of her, snaps. This is somehow not what she expected, and why she had expectations for what sex with herself would be like, she doesn't know. Joan clutches John's hands hard enough to bruise, and he clutches right back, and she cannot for the life of her remember when they twined their fingers together like that, and Sherlock's vigil is so insistent, _burning_ and filling her mind with smoke, and both she and John look at him standing in the doorway.

"Get over here," Joan demands.

"Right now," John adds.

* * *

Sherlock doesn't need to be told twice. His heart is pounding madly; he feels as though his blood is spiked with cinnamon. He crosses over to the body and raises shaking hands to the buttons of his shirt and curses them for not being still, for not being in control, because he thinks that's what John and Joan both need. He isn't sure. He still has yet to master emotional interpretation, and what he just witnessed—a screaming minute so packed with feeling that it was like being caught up in a whirlwind, and he wondered, for a moment, if that was what John had tried to describe to him before when he'd said "your emotions can fill up a room"—has left him gasping. Like he's stepped into a lake only to remember he can't swim.

John grabs his wrist and pulls him onto the bed, and Joan grabs him by the collar of his shirt, and kissing her is like sliding beneath the surface. He drowns in her mouth even as he sears facts into his memory; the chip in her left molar that is identical to John's, her way of swirling her tongue around his like they're fencing, the rumble from the back of her throat that spills into him like light. He is burning, he is _burning_. Possessiveness swells in his gut and keeps on until Joan pulls away desperate for breath, which is fine, because John is there to pick up the slack.

They maneuver Sherlock between them, and in the back of his mind he realizes that he is there as a barrier, to protect them from a level of intensity that they couldn't bear to face. They rain kisses down upon him and let him mark them with his teeth and nails and fingertips, and he realizes that he is also there simply because they want him to be.

Sherlock lets his mouth fall to one of Joan's breasts, cupping the other with his palm, and John kisses his back, and Joan gasps higher than any noise John has ever made, and he sets about trying to wring as many of those sounds out of her as possible while appreciating how it feels to be not just a desire, but a necessity.

* * *

John drags his teeth over Sherlock's shoulder. There is a perfect melody echoing throughout him, with a rhythm he's never felt, an instrument he's never been privy to until now and that it feels like he himself is playing. Joan is breathy and beautiful and he groans low in contrast and Sherlock, Sherlock hums, pitched between them like he's planned it to be so.

Every nerve in him is awakened. Staring Joan in the eyes, seeing himself reflected both literally and figuratively, was the biggest jolt he thinks he's ever experienced. That closeness had toed the dangerous line between pleasure and pain, between delight and torture, and they had both agreed silently not to throw themselves into the abyss, because where would it have gone? He'd seen it all in her eyes and known she was seeing it in his, and it had been so overwhelming, and he clings to Sherlock because he is erratic and otherworldly and strange, but still so constant. His back muscles ripple beneath John's hands and lips, his arse presses back against John's hips—

John's and Joan's hands tangle up over the zipper of Sherlock's trousers, and he hears her laugh, such a flawless complement to his, and his heart seizes—

He lets her undo the trousers, but John pulls them down, and Sherlock allows them to manhandle him with a dazed expression. They get him undressed and John is stricken, as always, by how gorgeous Sherlock is, pale and angular and sculpted like the faded statues of the ancient Greeks, the energy in him almost visible beneath his skin, young and tight and so perfect. With Joan behind Sherlock, John can see the stark contrast between their tones, and he is filled with hunger.

He ducks his head down to wrap his lips around Sherlock's cock because his tongue is aching for it, and because he wants to feel Joan and Sherlock watching.

* * *

John's head is nestled between Sherlock's thighs, and Joan thinks she has never needed as she does now. She itches with desire, burns with it; she wants to be pried apart, filled, even if it ruins her for everything, even if sharp worry spikes in her brain (what if this is the best, what if I go back and it's not enough, what if, what if). It doesn't matter. Now that she's had a taste, she needs it all. She was never this way before falling in with Sherlock. She was never this reckless.

"Stop thinking," Sherlock says, rolling his head back to set heavy, hazy eyes on her face. Joan opens her mouth to say... something. What if this is too good? What will I do when I go back? What if I can't go back? But Sherlock has retained enough presence of mind to reach behind him and shove his hand down her pants, and his fingers are just like her fingers, the Sherlock she knows; his fingers rub and circle and push just like hers.

Joan very nearly surrenders herself completely, but Sherlock lets up the pressure for a second as he gets lost in his own pleasure, and she sighs, "John." He looks at her, lips wet and clinging to Sherlock's cock, then pulls up, tongue trailing slightly behind. Sherlock's hand goes still, and then he pulls it from her pants and she keens embarrassingly, then rushes to get off the rest of her clothes while Sherlock strips John.

* * *

Navigating the thicket of sensation takes concentration, but Sherlock forces himself to do it, because they need release, and they need it soon, so they need a plan. When it dawns on him, it's almost stunningly obvious. He presses a fleeting kisses to the head of John's cock when his pants are off, then goes to rummage through the bedside drawer. He comes back with lube and condoms and confidence.

"I want to fuck you," he tells Joan frankly, ignoring the tremor in his voice that he knows is almost all lust. There's no need to hesitate or feign modesty; Joan is as much his as John is, regardless of their short acquaintance in this reality. "And I want you to fuck me, John."

"Christ," John groans intelligently, and Joan mutters, "Sherlock sandwich." They look to each other, grinning despite their flushed skin and hard nipples and John's cock jutting into the air and Joan's lips swollen and glistening, and Sherlock needs them. Desperately. Before he tears off his skin for want of release, or something equally ridiculous.

It's so easy to place himself between them, to become the center of their attention. Sherlock can feel his ears and neck and shoulders flaring up, red from arousal and pleasure and maybe just a bit of nervousness, a bit of embarrassment, as Joan murmurs encouragement and John presses lubed fingers into his arse. He gives Joan a hand of her own, sometimes mimicking the twists and stretches John gives him, because it just feels right, to have them all connected so. Humiliating noises are crawling up out of his throat, endearments spilling from him freely, and Joan is so wet, he wants to give her more of himself, and if John doesn't _get in him_ soon he might die—

* * *

Joan falls onto her back and grips Sherlock's biceps and he pushes into her, rubbing his thumb on her clit all the while, past her lips and _in_ , only halfway buried but so so good—

* * *

John waits until Sherlock is fully in Joan, out of some odd sense of chivalry, and then he can wait no longer; he slides into Sherlock and feels the two move beneath him, hears the hitches in their breath and their pleased little sighs, and then quite suddenly they're all moving—

* * *

They find a pace after some mindless writhing in which Sherlock couldn't decide whether to push back against John or push forward into Joan, because both are so enticing; it's impossible to choose, he must simply alternate between the one and the other.

After John thrusts, Sherlock has to thrust as well, and Joan tightens around him; John kisses his neck and shoulders, licks his sweaty skin, breathes him in; Joan scratches his arms, his sides, kisses him with wild abandon; John's hand is on Sherlock's stomach; Joan's hand is trapped between John and Sherlock; they both curse so colorfully that Sherlock laughs out loud and he cannot stop, everything is just so bloody _good_.

Sherlock worships every part of Joan he can reach with his mouth and his hands; he clenches around John and sometimes has to struggle for breath because he's been thrust into at the perfect angle; he loses himself, and he clenches the sheets, and he utters their names like prayers, and they respond with gusto.

* * *

Come morning, John feels boneless. He will never move again, he thinks. Sex that good probably requires a sacrifice, and his legs were deemed the fairest trade, never mind the psychosomatic limp.

"If he existed, I would never give the devil your legs," Sherlock mumbles into his pillow.

"How did you know I was thinking that?" Joan asks from his other side.

"You both think with loudspeakers. Distracting."

John huffs, then nuzzles into Sherlock's side, eager to wring out a few more minutes (or hours) of sleep. He can repay him for that comment later. Joan's knuckles brush John's stomach as she wraps an arm over Sherlock, and he is content.

* * *

Sherlock's eyes snap open one hour and nineteen minutes later, because he has figured out the answer to the puzzle, and it's so _obvious_. He should have seen it immediately. John and Joan wake almost immediately after he does, which is good, because extricating himself from their embraces would have been difficult enough that he might have just stayed in bed instead. Now that he's spared the trouble, he surges up and off the bed, and paces, trying to explain it to them.

"It's bloody hard to take your raving seriously when you've got your cock swinging around," Joan reflects.

Sherlock stops with the hope that it will make his Watsons pay attention. "I've figured it out! We just need to replicate the conditions that brought you here, and you should be able to go back. It's all so _simple_ that it's absolutely genius; the intricacy of it all is astonishing, I—" He pauses. He knows the hyperdelicate tension that fills the room now, and he looks between John and Joan, trying to understand why they've shut down... ah.

"You need to go back," he says as gently as he knows how. "Not because I don't want you, but because I do. The me where you're from, she needs you. I need you." He doesn't mention that he also suspects that having two of one person in the same universe for any significant amount of time might rip the fabric of space/time, or that it might rip _them_ and eliminate his Watsons from existence, but those are concerns as well.

* * *

"Well," Joan says, rather breathlessly.

"Well," John replies in kind.

She locks eyes with him and they clear their throats and dance around awkwardly while Sherlock opens windows throughout the flat. "It was..."

"Lovely?" John suggests.

"I was going to go with something closer to, 'like meeting my other half,' but lovely is good as anything." Joan's grin is wry, but her voice is weighted with words that go unspoken. They don't need to be said. A breeze shoots through the hallway, and the closet door that John is keeping open bumps against his back, and Joan thinks it's very strange to be close to tears about saying goodbye to herself when she can't very well leave herself, because she is herself, damn it. But she isn't him, and he isn't her, but they are.

Interdimensional travel is absolute shite, she decides.

Sherlock comes back to the hall, and the door bumps against John's back again, and Joan is still screwing up her courage when John blurts out, "God, I love you."

"Narcissist," Sherlock intones. His face is straight but his eyes are fond, and Joan has always been one to laugh at her own jokes, hasn't she? She laughs with John for the last time, although really it's not, and she steps into the closet and stretches up onto the tips of her toes, grasping for the shelf and John lets go of the door. Her fingertips scrape the edge of the shelf, she pulls herself up, and—

The closet door slams shut.

* * *

"Joan?" Sherlock asks, opening the door. She peers down at her flatmate with concern. "I... Is there a reason you're crying in the closet? Are you all right?"

Joan shakes her head, choking on laughter and tears, and can't bring herself to form words. She pulls Sherlock down and kisses her until she can't breathe anymore, and when she pulls away, Sherlock looks more alarmed than ever.

"I'm sorry I asked you to get this box," she says gravely.

Joan laughs, because she loves Sherlock, because Sherlock thinks retrieving a box sent her into hysterics, because she can remember their male counterparts so crisply, because there's still a dull ache between her thighs and, "God, I love you," she says.

Sherlock makes her lie down for the rest of the day and checks her for fever, and Joan couldn't be happier. Sherlock will be so enthusiastic about the mystery of their space-bending closet.


End file.
